A hearing for jockey David Walker over charges of illegal riding has started at Wellington Racing Club at Trentham.
The Race Integrity Unit has investigated allegations that Walker bet on another horse at a race meeting last month, and pulled up his own horse to ensure he won the bet.
The unit said it had also uncovered concerns about Walker's behaviour at some other recent race meetings.
The 38-year-old turned up to the hearing without legal representation. He is supported by his father Jim, a former jockey, and his wife.
The jockey faces a possible lifetime ban from racing if found guilty.